Sources of the Levantine Intermediate Water in Winter 2019

Abstract

Climatic changes and interannual variability in the Mediterranean overturning circulation are crucially linked to dense water formation in the Levantine Sea, namely the Levantine Intermediate Water whose formation zone, comprising multiple and intermittent sources, extends over fluctuating pathways. To probe into the variability of this water formation and spreading, a unique dataset was collected during the winter of 2019 in the western Levantine Sea, via oceanographic cruises, profiling floats and a glider, at a spatio-temporal distribution suited to resolve mesoscale circulation features and intermittent convection events. This study highlights the competition between two source regions, the Cretan Sea and the Rhodes Cyclonic Gyre, to supply the Mediterranean overturning circulation in Levantine Intermediate Water. The Cretan source was estimated as the most abundant, supported by increasingly saltier water masses coming from the Levantine Sea under the pumping effect of a water deficit caused by strong western outflow toward the Ionian Sea.